Wrench



Dec. 18, 1945. A. ERTNER 2,391,143

WRENCH Filed Oct. 2, 1943 inventor August C. E'rtner Gttomeg V cientandconvenient tool.

Patented Dec. 18, 1945 {f /UNITED STATES, PATENT: OFFICE WRENCH August0. Ertner, Seattle, Wash., assignor to Fed- ,eral Trading 00., Seattle,Wash.,=a partnership composed .Thorn I of August 0. Ertner and J. FrankApplication October 2, 1943Q'SerialNo.504,727

2 Claims. (01; 31 -152) My invention relates to a quick adjustablewrench, and more specifically to the particular type of jaw holdingmechanism employed. 'While my wrench jaw holding mechanism maybeincorporated in wrenches of different types, in 'any'fsuchinstallationthe user may merely push the movable jaw towards the fixed jaw, thus togrip the work between them, without 'di frectly manipulating the jawholding mechanism,

The movable jaw will be held automatically in such work grippingposition against great force tending to separate the jaws. Despiteability of thejaw latch to resist displacement of the movable jaw underworking load such jaw can be released by a simple manual operation formovement away 'from thefixed jaw.

f It is therefore anobject of my invention to provide jaw latchingmechanism which will be moved automatically into holding positionwhateverthespacing between the jaws maybe, so that it 'will'be'incondition at all times to resist movement of 'th'e movable jaw away fromthe fixedfjaw by a force'reacting between them; Nevertheless the movablejaw may be quickly retracted at will from the fixed jaw, and over'anydistance, by manually releasing the latch mechanism.

"More specifically it is an object to provide a latch constructioncapable of afiording such operationwithout being. injured by a heavyload which can be withstood by the other wrench parts, and withoutslippage of the movablejaw 1 upon initialapplication of the load. Thelatch ing mechanism is therefore positiv and self-act An additionalobject is to provide a latching wrench having such capabilities butcomposed of few parts, which; can be produced by simple machineoperations, and which can be assembled readily to afford an economical,yet an effi- LOtherobjects of my invention which resultfromthe'particular nature and characteristics of the mechanism-which Iprefer will'be understood from I the following detailed description of awrench construction typical of my invention. It will be understood thatthe: wrench shown in the drawing is only representative, being one typein which my latch'can be used, and various' details of the latchconstruction can be altered as desired while embodying the importantfeatures defined more particularly in the appended claims.

LFigure- 1 is a top perspective view. of a wrench embodying my latch,with parts broken away to reveal the latch structure.

Figure 2 is a side elevation view of the wrench head, with part of thecasing broken away to expose internal structure, and Figure Bis a rearelevational view of the wrench head.

Figure 4 is a plan'view of a latch plate removed from the wrench. Figure5 is a perspective view of one type of latch spring which may beemployed. 7

As a typical embodiment of my invention I have illustrated in thedrawing a monkey wrench includinga fixed jaw l' integral with a rectan'gular shank I0, which shank projects through an aperture 20 in a movablejaw 2, guided by the shank for reciprocation toward and away from thefixed jaw I. The end of the shank remote from the fixed jaw forms thehandle. It will be understood that the particular shape of the jaws Iand 2, the manner in which the jaw I is mounted on its shank l0, and theangular relationship of the 'jaws to the shank are matters of choice,-and may be varied according to the particular type of wrench embodyingmy latch mechani'sm, and the use for which the wrench is intended. Thelatch construction described below is interengaged between the movablejaw 2 and the shank Ill, irrespective of th particu-' lar jaw structurefeatures and the extent of movement of jaw 2 along the shank l0.

'The latch construction, to which my invention particularly relates, isenclosed within a case 3, preferably 'made of sheet metal, which may besecured to the lower portion of the movable jaw '2 in any suitablemanner, such as by a screw 30. It will be understood that the aperturein the bottom of this casing through which the shank l0 projects, andthe hole 20 in the movable jaw itself, are of a size to affordsufficient clearance for the shank to slide easily" through them withoutbinding. Neither the movable jaw' nor the case is relied upon to assistin gripping: the shank'for the purpose of holding the r'novable jaw fromsliding along the shank.-

The latch mechanism proper consists of a p1urality of thin plates-3|, atleast two in number, each having a body portion of a size approach ingthe inner cross section of the casing 3.

for example the shank may project through a of the plate lengthappreciably exceeding the width of the shank parallel to the jaws l and2,

. so that such plates maytilt at a substantial an-E Each latch plateembraces shank l0 somewhat loosely},

gle relative to the shank. Moreover aperture 32 is preferably locatedconsiderably nearer one end of the plate 3| than the other, to form atongue projecting transversely of the wrench shank for a substantialdistance beneath movable jaw 2. The tongue of the upper plate 3| abutsthe bottom of a shoulder 2| projecting froina portion of jaw 2 lremote'fromthawrench shank '10 down ward well below the portion thereofthrough which the shank passes. Such shoulder is inclined relative tothe shank so that its portion most remote from the shank projectsfarthest downward, as will be discussed more fully hereafter.

Because aperture 32 in eachplate 3| *is longer than the correspondingtransverse dimension "of the wrench shank, each latch plate may tiltthrough a substantial angle relativeto'theshank Asthe force :is appliedthe'sliding jaw will tend to move away from the'fixed jaw, that isdownward in Figure 2, and the jaw shoulder --2! will press againsttheouter endof the tongue of the upper'latch plate 3| at a locationsubstantially beneath the center of the gripping-partof jaw 2 projectingbeyond shank l0. Such-pressure will tilt ithe'upperlatchplate-bytheleverage thus ex-' erted,.and in succession eachlatch-platebeneath it,.in a direction so that the lower corner of the apertureedgeinext to thetongue and the upper corner of the aperture edge remotefrom the tongue-will ibitesimultaneously against the shank.

Assumingthat the apertures 32 in all .the overlapping latch plates-:3!are of the same length, the corresponding corners of all the apertureswill thus bite "similarly against shank I0 simultaneously,cas-shown inFigure .2. Even though the latch plates mayberather thinrand may tend tobe bent *by the force *exerted on-their tonguesby the jaw shoulder, anydeflection whichoccurs will act to increase thegripping effect of eachplate upon=the shank. No individual latch plate can be deformed beyondits-elastic limit, however, because each plate in turn-supports the oneabove it, and all ftherefore actin concert to withstand thestressexertedon them by pressure of .thejaw shoulder 2 I.

It'isto .be noted particularly how'the pressure of thejjawshoulder'against-the tongue of the upper'latch plate is transmittedsuccessively' toeach of the underlying latch plates. All these latchplates abut contiguously, and preferably the holes 32 of all the platesare of precisely :the same length. If there is any variation in thelength of .such holesthe hole in each underlying plate should not exceedthe length of the hole in the platenext above it. Only where the platesare of :su'hiciently thin :stock '130 be somewhatyieldabl lunder'loadsusually to beexpected, a-slight variation may not be too detrimental. Inthat event, 'the'plates all being in contiguous face-toface "engagement,the tongue of each under plate would bendslightly before the plate nextwabove itwould grip the shank.

In order to insure substantially immediate'gri ping xofiall the latchplates against shank [0 a spring 33, encircling the shank-isinterposed-between the bottom of the'cas '3 'andithe aperture'd end 0fthe lower latch plate. The specific shape ofzsuch spring is not.ofli'great importance, :but

that shown in Figure 5 has been found to be effective and is verycompact. This spring, of the compression type, acts against theapertured ends of the latch plates in a direction toward fixed jaw I totilt the latch plates about shoulder 2! as a fulcrum, that is, in thesame direction as pressure by the jaw shoulder tends to tilt the platesrelative to shank "HI. Thus :upon application of a force reactingbetween the jaws the latch plates will merely be forced more tightly"against the shank, already being located properly lengthwise of theshank to exert the requisite holding action. The only separatingmovement --of 'the' jaws which can occur under load, there- "fore, .isthat'corresponding to the deflection of the tongues 'ofthaplates.

In order to exert the maximum leverage action-on thellatch, plates fortheir length it is desirable that the jaw shoulder 2| engage the tongueof the upper plate at a considerable distance fromtsh-ank ll].Anticipating the possibility of some slight deflection of the latchplates under heavy load,-the lower end-of the jaw shoulderis preferablyinclined relative to shank H1 :at fan angle somewhat greater than themaximum Y angle-at rwhich the latch platetongues can be tilted when theplates are in gripping attitude. The shoulder thus engages theuppenplate tongue at all timessubstantially along a [line immediatelybelow the central portion of the part of jaw 2 projecting beyond shankNJ, to leave clearance between such tongue and theportion of the jawshoulder-nearer .shank 10 under all loading conditions.

Sincetilting of'the-latchplates 3| to decrease the angle betweenthem-and shank 10 accomplishes a gripping action to restrainsliding ofthe movable jaw along the shank, it will be-evident that thelatchrplatesmay be released from the shank, to --enable themovablejawto be slidalong .it, hy-tilting them in the=opposite direction. Such movementincreases the angle between the latch plates and the shank, moving themintoa position more nearly perpendicularto the shank so that clearanceisaffordedbetween the latch plateapertures and the shank.

Such latch releasing tilt of the latch plates maybe accomplishedpositively by engagement of the operatorsthumb with a tab 34 projectingfrom the end of the upper latchplatelil opposite the latch plate tongue..As shown in Figures 2 and3, 'thistab projects through a slot in theback of the casing, so that itmay be engaged readily. Preferably all theplates have'such tabs, sothat the releasing pressure is transmitted'fromone plate to the next at a location reasonably far from the slide. It isnot necessary, however, that more than'the uppermost 'plate have sucha'tab. If the lowermostplate also has a similar tab 3-4, however, itmayserve as -a seat for a'rearwardly projecting loop of spring "33; asshown.

The operation of mywrench will be-readily apparent. The movable jawmay'simply-be pushed toward the fixed jaw, during which operation thel'atchplates will slide along the shank, since there is no load on them.In fact, if thetongue of the lower :latchplate is engaged zby the case3,:the plates would all be tilted positively toward released position,mzorenearly perpendicularto the shank. Nevertheless"whenever the:movable jaw comes to rest'spring 3-3 will'immediately push the latchplates away from the bottom of the case, so that the'tongue'of theupper'latchplate will be pressed against shoulder 2|, and ?.the i-plateswill she tilted :substantially :into .;shank gripping latch plate tab34.

shoulder 2| on the latch plate tongues is considposition. When the loadis applied on the wrench, therefore, creating a force tending toseparate the jaws, the pressure of shoulder 2| on the upper latch plate,transmitted in turn to the underlying latch plate, will tend to tiltthem relative to shank H1 in a direction to grip it tightly.

Because the latch plates are in contiguous face-to-face contact, eachone supports the other over substantially its entire area to aflord anintimate, distributed supporting action. Even though each plate is madeof material so thin that the force exerted by jaw shoulder 2| wouldreadily bend it, if used alone, the stacked arrangement of the latchplates, in which they act conjointly, will prevent deflection of anyplate to an extent which would result in its permanent deformation orbreakage. Furthermore, while a single latch plate would not affordsufiicient gripping action because only two corners would be pressedagainst the shank, where a plurality of latch plates are provided twocorners of each exert a gripping force, so that even with two plates asatisfactory holding action is effected, which a single latch plate willnot produce. Each additional plate will add two more gripping edges, buttwo or three plates will usually afiiord all the holding actionnecessary.

As long as any substantial load is applied between the jaws the latchplates will be pressed against the shank too tightly for them to bereleased even by pressure of the thumb on the upper The leverage of thejaw erably greater than that afforded by pressure on the plate tabs. Thegripping action of the latch plates therefore cannot be inadvertentlyreleased, even if the wrench is being manipulated by two hands.

When pressure on the movable jaw is relieved, however, pressure on thelatch plate tabs 34 will tilt the plates readily into released position,be-

cause of the considerable leverage offered by such tabs. The movable jawmay then be slid readily away from or toward the fixed jaw to any extentdesired. Although it is not necessary in most instances to apply manualpressureto the latch plate tabs in order to release the platespositively for closing movement of the jaws, such reciprocation may befacilitated in some instances by such manipulation, especiallyimmediately after the wrench has been subjected to an unusually greatload which tends to set the latch plates tightly against the shank.

It will be seen, therefore, that with my latch construction the wrenchmay :be operated readily for either opening or closing movement of thejaws by one hand, and the desired jaw movement may be accomplished veryquickly. Despite such case of adjustment'the provision of a plurality ofcontiguously engaged latch plates produces an immediate and suflicientlypowerful gripping actionto prevent any appreciable slippage of themovable jaw upon application of a load or thereafter, however great suchload may be within the capacity of the wrench as a whole.

I claim as my invention:

1. A wrench comprising a fixed jaw, a shank integral with said fixed jawand projecting generally transversely therefrom, a movable jaw slidableon said shankand having a shoulder projecting from the side thereofopposite said fixed jaw and located remote from said shank, the end ofsaid shoulder being inclined toward said shank and fixed jaw, and'aplurality of thin latch plates disposed in contiguous face-to-facecontact, apertured to embrace said shank and engaging said movable jawshoulder, being tiltable by pressure of said shoulder thereon, by aforce acting to separate said jaws, into pinching engagement with saidshank at an angle relative "thereto slightly greater than the angle ofinclination of said shoulder end relative to said shank, to preserveline contact between said plate and the side of said jaw shoulderfarthest from said shank under usual loads, thereby restraining slidingof said movable jaw along said shank away from said fixed jaw, saidlatch plate being en- "gageable with an appreciable area of said fixedjaw shoulder upon bending under excessive loads,

such engagement limiting the degree of possible bending of said plate.

2. A wrench comprising a fixed jaw, a substantially rectangular shankintegral with said fixed jaw and projecting generally transverselytherefrom, a movable jaw slidable on said shank and having a shoulderprojecting from the side thereof opposite said fixed jaw and locatedapproximately at the center of its gripping part projecting from saidshank, the end of said shoulder bein inclined toward said shank andfixed jaw, a plurality of thin latch plates disposed in contiguousface-to-face contact and having a substantially rectangular aperturetherein to embrace said shank, each having a tongue projecting asubstantial distance transversely from said shank to a location beneathsaid movable jaw shoulder, the tongue of th latch plate next to saidmovable jaw engaging said movable jaw shoulder, said latch plates beingtiltable conjointly by pressure of said shoulder on'the latch platetongue engaged thereby, by a force acting to separate said jaws, througha substantial angle into pinching en agement with said shank at an anglerelative thereto greater than the angle of inclination of said shoulderend relative to said shank, to preserve contact between said plate andthe side of said jaw shoulder farthest from said shank along a lineperpendicular to the movable'jaw and substantially directly beneath thecenter of its gripping part, thereby to restrain sliding of said movablejaw along said shank

